In the chilly pre-dawn gloom one recent morning, Father Makarios hurried to his chapel, one of dozens of churches and cathedrals across Mount Athos, to perform morning liturgy. A two-hour marathon of biblical recitations and sonorous chanting, it would be just one of many services that day.

After the liturgy, Makarios, a 68-year-old Greek monk who has lived on Athos for 51 years, changed from his white prayer robes into his habitual black attire and doled out spiritual advice to a group of Belarusian businessmen who had made a pilgrimage to see him, over an austere breakfast of coffee and nuts.

For centuries, Orthodox men have come to Mount Athos, a closed peninsula in northern Greece, to sequester themselves away from the everyday concerns of the outside world. The only entrance is by boat, and women are strictly forbidden to set foot on the territory. Male pilgrims, after receiving a special permit, can visit to confess and seek counsel from the 2,000 monks at the 20 monasteries and smaller “cells” dotted along the hilly shoreline. It is one of the holiest sites of Orthodoxy, the eastern form of Christianity that split with Catholicism in the 11th century.

All is not well in Orthodoxy currently, with a split linked to Russia’s war in Ukraine causing a schism and dark talk of violence among the various Orthodox churches. Bartholomew of Constantinople, known as the ecumenical patriarch and the “first among equals” of the Orthodox patriarchs, agreed in October to give autocephaly to the Ukrainian Orthodox church, essentially making it an independent church. Patriarch Kirill of the Russian church, which regards Ukraine as its domain, responded furiously and announced a split from the ecumenical patriarch.

With a meeting in Kiev on Saturday set to formally proclaim the church’s independence, some are predicting violence if Kiev tries to seize church property from the Moscow patriarchy. The ripples from the decision are being felt far away on Athos, which is under the control of the ecumenical patriarch, whose name is blessed during services.

“Ukraine is an independent country and deserves its own church,” Makarios told the visiting Belarusians, who nodded dubiously. His view is not shared by all: a Ukrainian monk based at Makarios’s cell, Father Agafon, had a different opinion, calling those Ukrainians in favour of an independent church “splitters and heretics” and saying the Ukrainian church should remain under the control of Moscow.

Although most of the monks on Athos are Greek, for many Russians, as well as Ukrainians and Belarusians, a pilgrimage to Mount Athos has become almost like an Orthodox version of the Islamic hajj, seen as a spiritual must for any true believer. Oligarchs and government elites particularly like the peninsula, with its difficult-to-obtain permits and air of a VIP club. In the weeks prior to the Guardian’s visit, Makarios said he had hosted a Belarusian army general, a number of Ukrainian MPs and several rich Russians at his austere cell.

They come seeking blessings, forgiveness and, sometimes, advice from on high about business decisions. “I answer the questions that have to do with God and with life and with death, this is what I think is my task, but I am not a businessman. How am I supposed to answer questions about business?” he said.

Kirill has banned Russians from taking holy communion in the churches of Athos, calling any priests who bless the ecumenical patriarch schismatics, leading to a dilemma for those Russians who want to visit.

One Russian who has been particularly active on Athos is Konstantin Malofeev, a businessman known as the “Orthodox oligarch”, who is currently on EU and US sanctions lists for his alleged role in funding the separatist insurgency in eastern Ukraine.

Malofeev said in an interview that he first travelled to Athos in 2004 and “could feel the presence of the Holy Virgin” on the peninsula. After that he visited at least annually, until sanctions curtailed his trips.

In 2013 he arranged for the Gifts of the Magi, relics held in the St Paul’s monastery on Athos, to tour Russia and Ukraine. Devotees queued for up to 15 hours in freezing temperatures in Moscow and other cities to catch a glimpse of the relics, which they believe to be the gifts given to Christ by the three wise men. There were rumours in the Russian press that during the stop-off of the relics in Crimea, negotiations over the upcoming annexation were held. In 2016, Vladimir Putin visited Athos and attended a service at the Panteleimon monastery, where most of the monks are Russian.

Much of the time on Athos, watching the monks pray, tend their allotments and receive pilgrims, their hair pulled back tightly in knots and beards flowing freely, geopolitical concerns seem of another realm entirely.

Once on the peninsula, there are few cars with which to navigate the unpaved, serpentine roads between different monasteries. Athos runs on Byzantine time, an archaic system in which the clocks are reset each day at sunset, and it uses the Julian calendar, rendering Athos 13 days behind the rest of the western world. At sunset the monasteries shut their gates and a stillness settles on the peninsula until the bells ring for morning liturgy.

Lunch is the one hot meal per day, with breakfast and dinner austere snacks of biscuits, nuts or olives. Meat is banned. At some monasteries, meals are eaten quickly and in silence, while at others there is jovial conversation at the dining table.

“People come here to try to be saints, and leave the difficulties of the world behind,” said Father Porfirius, a 27-year-old Greek monk. “The hardest part is to kill your will. We try to destroy it, to get to the level of obedience of Jesus Christ.”

Yet it does not take long to notice that not all the monks live in full isolation from the outside world. Father Alexander, a 52-year-old from Luhansk in eastern Ukraine, wears the orange-and-black St George’s ribbon, symbol of the Russia-backed separatists, tied to his monk’s robes.

A former Soviet military pilot who took part in the cleanup operations around Chernobyl and in the Soviet military action in Afghanistan, he later flew helicopters as part of the Ukrainian military on secondment in various war zones. He became a monk and moved to Athos in 2011, living at Koutloumousiou, one of 20 main monasteries on Athos.

Aerial view of the the Holy and Great Monastery of Vatopedi on Mount Athos. Photograph: Athanasios Gioumpasis/Getty Images

When conflict broke out in his home region in 2014, he returned home to provide support to the separatists fighting Ukrainian government forces.

“The abbot gave me blessing to go to the war but said if you carry a weapon you will die. I asked what would I do in a war without a gun, and he said: ‘Fight with your words’. And thanks to my words, we destroyed half the Ukrainian aviation. I drew maps of how they would fly on a napkin and we shot them all down,” he said.

Alexander said Bartholomew, by granting independence to the Ukrainian church, was “sending 5 to 7 million people directly to hell”, and said it was “spiritually difficult” to continue praying in services where Bartholomew was blessed.

The debates over Athos are heard even more loudly outside the peninsula, as western nations suspect Russia of using Athos to gain a foothold in an EU nation. Geoffrey Pyatt, the US ambassador to Greece, made a well-publicised trip to Athos in April this year. Pyatt emerged as a Russian hate figure after the Maidan revolution occurred during his tenure in Kiev.

Pyatt said that since arriving in Greece he had seen many of the same Russian tactics at work that he saw in Ukraine, with businessmen buying up strategic interests and creating dubious networks of political and economic influence. “Of course they [Russians] don’t have the same levers of influence in Greece as they do in Ukraine, but the playbook is the same,” he said.

Father Makarios looking out towards the sea. Photograph: Shaun Walker for the Guardian

The Greeks, in a surprise move, expelled two Russian diplomats in August, accusing them of bribery and meddling in Greek affairs. One of those expelled was responsible for a religious society that looks after coordination between the Orthodox churches.

Malofeev blamed the Americans for the turmoil, claiming that “Pyatt is trying to stir up the same things he did in Ukraine” in Greece. He also claimed Bartholomew’s entourage was “infiltrated with CIA agents” and said the decision to grant independence to the Ukrainian church could lead to violence in Ukraine and Athos to split with the ecumenical patriarch.

On Athos, many monks declined to speak about this possibility. At the Panteleimon monastery, where Putin visited, the abbott asked for questions in writing, which were returned with a note that they were “not spiritual enough” to be answered.

Makarios said Russian designs on Athos were nothing new, with Moscow keen on the peninsula since tsarist times. “The Russians don’t like this place only for religious purposes. It’s a nice place for military purposes, on the Aegean Sea.”

He insisted that most of Athos was united in its loyalty to the ecumenical patriarch, but conceded that the feeling was not unanimous. “There are some monks who just love Russian money,” he said with a sigh.